Performance testing for existing web app

I'm maintaining a web app that has performance problems.

I want to record a series of actions, then play back those actions once I've made changes and compare page load times so that I can quantify the performance improvement.

The Selenium IDE does what I need for recording and playing back the actions, but I haven't found an easy way to record timings.

Is there a good way to record and compare page load timings using Selenium? Is there a better tool to use instead?

Which tool is used for web application testing?

Selenium In the list of open source automation testing tools for web applications This is the all time favorite tool of testers. Selenium is popularly known as one of the best regression testing tools that operate seamlessly over different browsers and platforms.

You might want to take a look at BrowserMob (http://browsermob.com/). You can upload your Selenium IDE test scripts and get them to run on your site. It's founder is the creator of Selenium RC, Patrick Lightbody.